In some prior constructions tensioning devices of this kind adapted to heavy duty use and having an arm mounted for angular adjustment on a base with meshing serrations on the meeting surfaces of these members to provide locked incremental angular adjustment of the arm were formed as castings of malleable iron including integral annular pads having alternate teeth and grooves forming the serrations. When so casting the serrated pads integral with the base and arm the size and spacing of the teeth which it was practical to form by this method was limited and therefore the increments of annular adjustment of the arm on the base was limited. Moreover, the serrations thus formed by casting of malleable iron invariably required costly machining of the serrations to insure suitable meshing.
In other prior constructions of these devices adapted to heavy duty use the base and arm were formed of rolled steel stock and machined serrated rings of similar metal were welded in proper position on the meeting surfaces of the base and arm. This method of construction was again costly inasmuch as the serrated rings were machined and then accurately welded in position on the base and arm.
Applicant has found that it is practical and considerably more economical than in prior methods of constructing devices of this kind for heavy duty use to construct the base and arm of rolled steel stock and to form annular pads on the meeting surfaces of the base and arm by indenting and cold flowing metal from the opposite sides of these members and in forming serrations in these pads by coining. By this method of forming the serrated annular pads the metal is cold worked providing stronger teeth which may be reduced in size to provide more teeth and therefore a greater number of locked angular adjustments of the arm on the base for a given diameter annular pad.